The present invention relates to spray nozzles that are used to spray abrasive suspensions or slurries. These spray nozzle designs are typically adapted to atomize a solids-containing liquid with a gas. Specifically, the present invention relates to a replaceable nozzle insert that can be constructed from a highly wear-resistant material and adapted to removably fit within an atomization port of a single- or multiple-port spray nozzle. Use of wear-resistant materials extends the overall life of the nozzle insert.
Spray nozzles similar to the type discussed herein are well known and have been used in a wide variety of applications, including spray drying, exhaust gas scrubbing and snow making, to name just a few. A few known multi-port spray nozzle designs are disclosed in U.S. Pat. Nos. 4,846,402 and 4,893,782. These spray nozzles are adapted to atomize a mixture of gas and liquid.
The atomization of solids-containing liquids, such as a lime slurry, can be extremely abrasive on the spray nozzles, and in particular on the atomization ports of the spray nozzles. When a particular application requires use of an abrasive liquid, the spray nozzles are typically sold with nozzle inserts that are adapted to fit within the atomization port or ports and that can be replaced after they become worn. The nozzles to date have been sold with replaceable nozzle inserts that are different from the nozzle insert of the present invention. As evidenced by U.S. Pat. Nos. 4,846,402 and 4,893,752, which are incorporated herein by reference, nozzle inserts are typically a single-piece, steel construction design having an upstream end adapted to threadably secure the nozzle insert into the inner body portion of the spray nozzle. Certain of these nozzle inserts include a necked-down portion for placement of an O-ring seal to create a seal between the nozzle insert and the atomization port, as disclosed by U.S. Pat. No. 4,846,402.
Unfortunately, however, such earlier nozzle insert designs are severely prone to erosion, especially when abrasive suspensions or slurries are atomized in the spray nozzles. While the steel construction of the earlier single-piece nozzle inserts is capable of supporting the necessary threads located at the upstream end of the inserts, the tool steel is not sufficiently resistant to erosion during spray nozzle use. Materials such as ceramics, for example, are not capable of supporting the threads required by the earlier nozzle insert designs. These materials are too brittle to be adequately threaded.
Accordingly, it is an object of the present invention to provide a replaceable nozzle insert design that provides for the use of highly abrasion-resistant materials in the construction of the replaceable nozzle inserts.
It is also an object of the present invention to provide a replaceable nozzle insert design that significantly increases the average life of nozzle inserts.
It is also an object of the present invention to provide a replaceable nozzle insert design that significantly reduces corrosion losses in severe environments, particularly in air pollution control acid gas reduction applications.
It is also an object of the present invention to provide a replaceable nozzle insert design that reduces the overall cost associated with nozzle insert replacement.
It is also an object of the present invention to provide a replaceable nozzle insert design that reduces the likelihood of complete nozzle insert damage, such as fracture for example, during nozzle insert installation, use, and/or removal.